The longest bone in the human body is the femur, commonly known as the thigh bone. The femur extends from the hip joint down to the knee joint and plays a crucial role in supporting the weight of the body during activities such as walking, running, and jumping. It is not only the longest bone but also one of the strongest, capable of withstanding substantial forces. The femur serves as an attachment point for muscles and ligaments, enabling movement and stability. Its length and strength are critical for bipedal locomotion in humans.